Toyota will recall another 2.2 million vehicles in the U.S. to fix a problem that could lead those products to suddenly surge out of control, it announced today.

The move was an unexpected and seemingly self-inflicted setback for a company that seemed poised to put the ongoing issue of so-called “unintended acceleration” behind it. The announcement comes a year and a day after Toyota’s top U.S. executive, Jim Lentz, apologized to Congress for delaying action on the runaway car problem. But it also follows by less than two weeks news that a federal investigation had ruled out mysterious electronic gremlins that might cause Toyota products to surge out of control.

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This is the third major recall by the Japanese maker to deal with unintended acceleration since October 2009 – and could raise questions about why it has taken Toyota so long to act. Last year, the maker paid a record total of $48.8 million in federal fines for failing to act promptly on safety issues, including problems with sticky accelerator pedals.

The problems may have their roots in Japan, but a news conference in Washington, D.C., on Tuesday, could play a pivotal role in determining the future of the world’s largest automaker.

The U.S. Department of Transportation is expected to release the results of a long and intense probe into the so-called “sudden acceleration” problem that has reportedly plagued Toyota products.

The maker acknowledged it had a pair of problems, first recalling millions of cars, in October 2009, due to loose carpets that could trap the accelerator pedal, then announcing a second recall three months later because of potentially sticky throttles. Toyota went so far as to shut down production at most of its U.S. plants, also halting sales of vehicles on dealer lots until it could make necessary repairs.

But critics have continued to insist that the recalls didn’t address alleged defects with the electronic control systems used to manage the maker’s vehicles. Any number of possible problems, from software glitches to electromagnetic interference, have been accused of causing some Toyota products to suddenly surge out of control.